Staged in the immersive Buenos Aires Coup Coup Club cabaret bar, These Trees are Made of Blood is a political piece that seeks to educate. I’m quite ashamed to say that I didn’t know about the ‘disappeared’ victims of the Argentinian junta’s Dirty War between 1976 and 1983; they number in the tens of thousands.

The Southwark Playhouse’s Little space is a gift for this kind of theatre, and the cabaret setup is instantly transporting. A folk house band play you in to tightly packed tables and chairs; the place is lit under fairy lights, bordered by curtains below a row of cardboard filing boxes, and peopled by cabaret artists who work the room gently. I bought into the environment quickly.

The show begins steadily with the country’s military leader, known as The General (Greg Barnett), compering the show. He delivers purposefully lame pun-liners, which work to establish a character we shouldn’t warm to. He moves us onto a number of cabaret acts that include a couple of the junta’s big wigs. The chief naval commander (Neil Kelso) – a particularly talented magician – is up last. and shows us one of the junta’s disappearances first hand.

In one of the show’s most successful moments, too much of a spoiler to describe here, the play shifts to the more personal story of Ana Benitez (Charlotte Worthing) and her mother Gloria (Val Jones). Mother has planned some bonding time, making empanadas together; daughter has plans to attend a mass student protest. There she disappears, and it is up to Gloria to find her.

From here on out, events are laid on pretty thick and the production’s structure begins to become its weakness. Episode by episode we learn new reasons to distrust the junta – the way ‘disappeared’ people are treated in camps; how parents are tricked into accepting what may or may not be their children’s remains in exchange for their silence; the ultimate doom dealt to victims. But this material needed to be handled with a lighter hand; my levels of shock reached terminal velocity too quickly and couldn’t be maintained. I left the theatre feeling a little sickened at myself for not being appropriately traumatised by what I had just learned.

The cabaret bar is successfully immersive, and works to facilitate twists in the plot, but it doesn’t transport you to Argentina itself. The light blue and white triband flags on every level surface are a heavy-handed touch. The colourblind casting of the actors and ensemble – mostly white British – doesn’t give the plot an everyman touch because its particulars are so specific to the country. If anything, it is in danger of sabotaging itself, retelling Argentina’s history in a post-Falklands British voice.

Though I was convinced by the performance of the Cabaret frame, I also found it highly problematic. Cabaret’s Kit Kat Club is too strong an influence on the similarly sounding Coup Coup Club. Kander and Ebb masterfully concocted the Weimar decadence vs Nazi control theme, and successfully replicated the device in The Scotsboro Boys’ minstrel show vs racial injustice juxtaposition. But there is no such link in These Trees are Made of Blood.

It is still a production with real strengths though. Darren Clark’s musical arrangement is outstanding throughout, often playing a key (and sometimes surreal) role in scenes. At one point Gloria is pushed over the edge by the quartet as the band’s drummer nonchalantly paradiddles on her kitchen equipment. Though the show didn’t move me as I’d wanted it to, it was the delightfully melodic playing of the ensemble that brought me closest.

Because I was not myself aware of the atrocities carried out by Argentina’s military junta, I feel that it is a story that of course needs to be retold. For ‘disappeared’ to also become the forgotten would be an insult to all that they must have suffered. But I left with the prevailing thought that their story would be told better by a more affecting production.

These Trees are Made of Blood is playing at Southwark Playhouse until 11 April. For tickets and more information, see the Southwark Playhouse website. Photo by Darren Bell.